Cover crops touted to save soil moisture

Saturday

Feb 23, 2013 at 11:00 AM

Just as multi-species cover crop mixes were becoming the hot new trend in conservation tillage circles, a devastating drought developed across the High Plains, leading many to question whether growing more plants to canopy the ground and increase soil microbial activity was even feasible.

By Candace KrebsContributing Writer

BURLINGTON, Colo. — Just as multi-species cover crop mixes were becoming the hot new trend in conservation tillage circles, a devastating drought developed across the High Plains, leading many to question whether growing more plants to canopy the ground and increase soil microbial activity was even feasible.

Cover crops evangelist Ray Archuleta won't take no for an answer when it comes to keeping a living cover on soil. In fact, he asserts mono-crop farming and fallowing practices that routinely leave the soil bare contribute to drought formation, as he goes all out in challenging farmers to think about plants and soil in a more holistic way.

"Do we create our own droughts?" he wondered aloud during one of several talks he gave at the annual High Plains No Till Conference. A nationally known conservation agronomist with the Natural Resource Conservation Service in Greensboro, N.C., Archuleta points out that bare soil heats up quickly in direct sunlight. The hotter it gets, the faster water evaporates from it.

"It's not about climate, it's about ecology," he said. "We went back and studied the prairies. And what we saw is that the more species you had growing, the more biomass you got. It's simple: cover it, feed it. You can't build soil organic matter with a wheat-fallow rotation."

Maybe so, but there's definitely a correlation between how dry things are and how much cover crop seed is being purchased, according to Brian Berns, a no-till farmer from Bladen, Neb., and co-owner with his brother Keith of a company called Green Cover Seed.

"When it rains, the phone starts ringing," he said. "There's been a lot of interest, but many farmers are waiting on a rain."

The Berns sell custom-made mixes comprised of up to 50 different plant species including legumes like clover, grasses like triticale, brassicas like turnips and many more.

"Cover crops are kind of that next step where no-till was 20 years ago," Berns said. "Farmers need to start out by doing it on a small scale and then they will have more confidence to do it again. I think the more we all learn about this the more we realize cover crops will improve the health of the soil and buffer you more against bad weather events when they do happen."

Trying something new

Hugo farmer Scott Ravenkamp admits it seems counterintuitive to plant additional crops in hopes of increasing soil moisture, but he hasn't been satisfied with the results of summer fallowing anyway. "In August, we typically get good rainfall. Where does it go by wheat planting time?" he wondered.

Last year, he learned he could grow a cover crop using only one and a half inches of water. After seeing how popular it was with the antelope, he decided to graze cattle on it.

So far he is in the early stages of his experiment, but one result he noticed right away was an increase in earthworms. He's not sure what an earthworm is worth, but he's pretty certain the increased activity is a good sign. He's also desperate for something to hold down his topsoil.

"We are in trouble in our area," he noted. "Our grass is starting to blow. I want to get something out there and growing."

Todd Randolph, an irrigated farmer from Walsh, shared favorable results from an on-farm trial of his own. Nearly out of irrigation water, he was still able to raise enough forage to have good grazing last year. In addition, he found himself pumping less irrigation water than usual.

"I'm impressed by what we've accomplished in this deal," he said. "It's taking us 8 inches rather than 12 to 14 inches to replenish the soil moisture profile. Typically I wouldn't think it would work like that."

A farmer and area soil conservation technician based in Springfield, Storm Casper, is also experimenting with dryland cover crops despite receiving only 6 and a half inches of rain last year. He urged farmers to have reasonable expectations. "The goal is to get something out there. It doesn't have to be tall," he noted.

Also from Springfield, Tim Steffens, a rangeland management specialist with NRCS, was equally sold on what plant diversity does for the soil. He said Eastern Colorado as it exists today isn't a true prairie; it's a buffalo grass monoculture. He envisions cover crop mixes bringing more health and vitality to the High Plains ecosystem.

"We can use some of these cover crops as a grazing crop and let these rangelands have some time to recover and deepen their roots," he said.

"As dry as it is right now, forage crops are going to be a pretty valuable commodity."

Fallow needed?

Mark Watson, the University of Nebraska's panhandle no-till educator based at Alliance, was skeptical about planting groundcover immediately behind wheat, then following up with a spring crop. "We're one-crop country," he said. "We can't raise two crops in a year up here. We need a longer fallow period."

In his own experiment, he found he needed 5 inches of irrigation water to get good growth from cover crops, more than he was willing to expend with conditions so dry. "That's not a good thing in my mind," he said.

"I think we are doing a horrible job of managing our groundwater."Still, he agreed wholeheartedly with the idea of adding more crop rotation and diversity.

"What we'd like to do on our farm is try replacing corn with forages and graze cattle," he said. "I think we can take some of these concepts and apply it, but we just can't do it as quickly as farmers who get 30 inches of rainfall a year."

Archuleta, who is originally from the county of the same name in Northern New Mexico, said diversity is the key. In a very diverse plant ecosystem, individual plants cooperate rather than compete for water, he claimed.

"It's counterintuitive to what we understand, but these plants are actually sharing resources. There has to be diversity or this won't work. We have to follow nature's template," he said.

The idea of bio-mimicry appealed to wheat farmer John Sauter of Keenesburg. He said he plans to launch his own experiment by planting field peas and other cover crops on 25 acres next year. "It's easier to work with nature rather than against it," he said.